We hear the legendary comic popped into Stand Up NY on Memorial Day, telling the manager he’d be back in 30 minutes and “would try to bring in people.”

Seinfeld merely tweeted he’d be taking the stage, and “over 50 people came in right away,” said an attendee. “It was amazing.”

The “Seinfeld” creator performed a 25-minute set, followed by a Q&A during which he told one fan “he’s done everything that he wanted to do — so now his favorite thing is to perform in front of audiences like this,” a spy said.